Who doesn’t know the problem of glare when trying to ogle a PCB underneath a microscope of some description? Even with a ring light, you find yourself struggling to make out fine detail such as laser-etched markings in ICs, since the scattered light turns everything into a hazy mess. That’s where a simple sheet of linear polarizer film can do wonders, as demonstrated by [northwestrepair] in a recent video.
Simply get one of these ubiquitous films from your favorite purveyor of goods, or from a junked LCD screen or similar, and grab a pair of scissors or cutting implements. The basic idea is to put this linear polarizer film on both the light source as well as on your microscope’s lens(es), so that manipulating the orientation of either to align the polarization will make the glare vanish.
This is somewhat similar to the use of polarizing sunshades, only here you also produce specifically the polarized light that will be let through, giving you excellent control over what you see. As demonstrated in the video, simply rotating the ring light with the polarizer attached gives wildly different results, ranging from glare-central to a darkened-but-clear picture view of an IC’s markings.
How to adapt this method to your particular microscope is left as your daily arts and crafts exercise. You may also want to tweak your lighting setup to alter the angle and intensity, as there’s rarely a single silver bullet for the ideal setup.
Just the thing for that shiny new microscope under the Christmas tree. Don’t have a ring light? Build one.
I am confused. I thought this was a sudo hoax thing a few years ago that EEVblog demonstrated.
https://www.youtube.com/watch?v=MvFf9RSJUhk
Is there a difference here that I am missing? NWR loves to make joke stuff from time to time so I assumed that was this without much thought so happy to be wrong.
Only watched the first 5 minutes of the EEVBlog video so I’m not sure where it ends up.
This is absolutely not a hoax.
The setup without the filters effectively sees a mix of the two pictures – everything is scattered and everything is crystal clear. The result is hard to make out.
Filtering the light and then filtering the view lets you pick for what’s optimal.
So the “hoax” part is that the before shot is worse than the plain view you have – but we all know alser etched parts are hard to read usually you can read part of it and then have to move it to read the rest.
The non-hoax part is that when you filter light and lens you genuinely can rotate it for a crystal clear view usually.
Um, did you even watch the video you linked? Dave demonstrates the technique working multiple times. I don’t know how you got from that to it being a “hoax”.
I remember seeing that video back then and it made me dislike Davey Jones a bit more. From what I remember (I’m not going to watch it again) he claims that you can twist and turn your PCB to get an effect that is somewhat similar to using polarizers, and then concludes the polarizers are nonsense. But it’s much more convenient if you orient the PCB in the orientation you want to work on it, and then adjust the built in lighting to see what you want to see.
Moving the PCB in an attempt to make text better readable does sort of work but it is by no means perfect. Polarizers work and they are a useful addition to your microscope.
And there are lots of other lighting tricks you do for example:
https://en.wikipedia.org/wiki/Dark-field_microscopy
Ring lights are another one. It removes most shadows and are very common, but if you are looking for tin whiskers, then the even lighting makes them nearly impossible to see. For tin whiskers, you want a light point source and then move both the light source and your work piece to catch some reflections from the very thin whiskers.
And those are just a few examples. There are more techniques that can help in some cases, but none are magic bullets that can solve any problem.
Or you can just tilt the chip a little bit.
When you do that under a microscope, it goes out of focus.
Adapting this to my microphone sounds pretty involved to be honest. Where does one even get a sound polarising film anyway?
Where to get polarizing film? From a junk LCD or Amazon. Even old things like calculators and cheap digital watches will have polarizing films in them. The stuff is everywhere, or you can buy a filter for a SLR camera or whatever, or even blow a paycheck from Edmonds or ThorLabs. Take your pick. I’ve done this, except for transmissive PLM, for qualitatively identifying certain evil minerals by using the lenses from fishing sunglasses from Walmart. You can get polarizing film if you try hard enough.
No, read the comment again. They’re making a joke about how Maya accidentally said “microphone” instead of “microscope” up top, although it’s been corrected since.
There already exists polarizing and duplex-adjustable polarizing filters for microscopes in a variety of configurations and sizes… from eyepiece inserts to objective inserts to stage-mounted conjugate ones that can be swung away(depending on the focal length of the objective)… there even exist ones for use with binocular viewers that use an external, “top down” light projection. Even polarized slides and films.
True, but polarized epi illumination is not so common. Which is a darned shame because it’s so useful and improves image quality so much. A good polarizer setup completely removes specular reflection and glare. I’ve been using it for several years.
The only downside is you throw away half your light power in the polarizer. My 24-watt “polaring” gets hot enough to require heatsinks, which makes the ring a bit heavy on the articulating arm.
I’ve noticed that sticking a piece of the orange “kapton” tape to the chip often makes the readings stand out better.